The present invention relates to compressors. More specifically, the present invention is a cable reinforced spring mounting system for attaching a motor-compressor to a hermetically sealed housing.
Hermetic compressors comprise a motor-compressor unit disposed within a hermetically sealed outer housing. The hermetic compressor is easily incorporated into an appliance by mounting the compressor to the appliance cabinet and making the appropriate electrical and fluid connections. However, compressors generate undesired noise and vibrations which can only be reduced by isolating the motor-compressor unit to suppress such noise and vibrations. To mount the motor-compressor within the housing, a spring mounting system is employed, including resilient springs which suspend the motor-compressor unit and suppress transmission of noise and vibration.
One spring mounting system is disclosed in U.S. Pat. No. 4,406,593, assigned to the assignee of the present invention, the disclosure of which is expressly incorporated by reference. The springs resist the vibration of the compressor by resisting both horizontal and vertical movement. Mounting studs are attached to the housing bottom and the bottom of the stator, with a connecting and supporting spring being engaged with a pair of corresponding studs. Each mounting stud extends into the interior of the connecting spring, limiting the possible vertical compression of the spring. However, the studs can only stop downward movement of the motor-compressor and do not limit horizontal or upward movement.
Another known spring mounting system for motor-compressors generally includes four components: a mounting plate, a mounting stud, a spring, and an insert. The mounting stud is attached to the lower part of the compressor housing, typically by spot welding. The mounting plate holds the motor-compressor unit and provides mounting locations for springs. The spring extends between and engages the mounting stud and the mounting plate. The tensile strength of the spring resists the upward movement of the motor-compressor, and the insert acts as a stop for downward movement. The insert is pivotal about the mounting stud and the mounting location on the mounting plate, allowing the motor-compressor to oscillate horizontally while still limiting downward movement. However, no provision is made for limiting upward movement.
A problem common with prior art spring mounting systems involves the motor-compressor abutting the upper portion of the housing due to vibration. To minimize the chance of contact and damage from abutting the upper portion, a relatively large space must be provided in the upper portion to accommodate the vibrating motor-compressor, or alternately space must be provided to accommodate stops. The housing, and therefore the entire compressor, must be sufficiently large to provide the large space for accommodating the possible movement of the motor-compressor or for locating stops.
An additional problem with prior art spring mounting systems is that they can be damaged when a lateral force acts on the spring simultaneously with a vertical force. This can happen when an assembled compressor falls to the ground on its edge, which sometimes occurs during transportation of the compressor after assembly. The resulting stress on the spring may deform the spring or alter its position relative to the compressor and housing either of which unbalances the mounting and may lead to more serious difficulties with the compressor components.
A further problem with prior art spring mounting systems involves the oscillation of the motor-compressor unit during starting and stopping. This horizontal oscillation about the shaft may result in overstressing and failure of the spring, and possibly some compressor components. To limit this oscillation, either stops or thicker springs may be employed. Stops require adding a component during assembly to the housing. Further, banging noise may result due to sharp impacts of the motor-compressor unit against the stops. Thicker springs inhibit the oscillation of the motor-compressor, but the increased stiffness of the springs increases the amount of noise and vibration transmitted from the motor-compressor to the housing.
What is needed is a spring mounting system which dampens vibration and limits excessive horizontal displacement of the motor-compressor.
Also needed is a system which resists downward movement without increasing transmission of noise and vibration.
A further need exists for a motor-compressor mounting system which minimizes the number of component parts.
Another need exists for a system which avoids using upward stops without employing a thicker spring.